Fixed TileMatrixSet definition. WMTS Simple requirement class

10 Copyright © 2013 Open Geospatial Consortium. Following reqsimple-profilewmts-profile-tile-url-template, if the name of the TileMatrixSet is empty, the URL template will have no reference to the TileMatrixSet that implies a CRS. This means that clients can assume that if no TileMatrixSet is specify, then it is assumed that tiles are in the Spherical Mercator CRS with URN urn:ogc:def:crs:EPSG:6.18:3:3857 . If a ServiceMetadata document exists, the exact definition of the TileMatrixSet in the ServiceMetadata document will be exactly as listed in Annex 0. If needed, you can define more that 19 zoom levels to support layers with better resolution. Currently, resolutions up to 24 are normal. Even if you declare an origin for the whole world, you can still advertise in the ServiceMetadata some TileMatrix limits by using the element TileMatrixLimits to declare the tiles that are actually available. Nevertheless, the client can decide to ignore this. Even if this TileMatrixSet is designed for representing the whole world, the Mercator projection cannot represent the poles correctly. If the server needs to represent the poles correctly, it needs to declare support to the profile http:www.opengis.netspecwmts- simple1.0confsimple-profileCRS84 and follow the next requirement. Req 8 reqsimple-profilewmts-profile-world-crs84 If the profile declared is http:www.opengis.netspecwmts-simple1.0confsimple- profileCRS84, a WMTS service implementing this profile SHALL additionally support another TileMatrixSet with identifier WorldCRS84Quad for all layers. This is a TileMatrixSet with all TileMatrix using a topLeftCorner coordenate of -180.0,90.0, with tiles values for TileWidth and TileHeight set as 256 and with WellKnownScaleSet iqual to urn:ogc:def:wkss:OGC:1.0:WorldCRS84Quad . If the server offers a ServiceMetadata document, this TileMatrixSet SHALL be defined only once for each server. If a ServiceMetadata document exists, the exact definition of the TileMatrixSet in the ServiceMetadata document will be exactly as listed in Annex 0. Again, even if you declare an origin for the whole world, you can still advertise some TileMatrix limits using the element to declare the tiles that are actually available. Nevertheless, the client can decide to ignore this.

6.3 Polar stereographic projection discussion

In OWS-9 it has been discussed the possibility to include a Polar Stereographic projection, it was suggested as a way to better represent Polar Regions, since Mercator projection is not able to represent Polar Regions and these are dramatically distorted in CRS84. In fact, it has become clear that there is a need to find an independent solution for the Antarctic and Arctic. Currently, for Arctic regions EPSG:3413 or EPSG:3995 and for Antarctic EPSG:3031 were suggested. Copyright © 2013 Open Geospatial Consortium. 11 In fact, currently NASA was tiled WMSs services are available at this endpoints: http:map1.vis.earthdata.nasa.govarcticwms.cgi Tiled WMS, Arctic Polar StereographicEPSG:3995 http:map1.vis.earthdata.nasa.govantarcticwms.cgi Tiled WMS, Antarctic Polar StereographicEPSG:3031 During OWS-9 a WMTS server in Polar Stereographic projection was deployed containing near-real-time imagery for the Antarctica taken by the NASA MODIS instruments: http:map1.vis.earthdata.nasa.govwmts- antarcticwmts.cgi?SERVICE=WMTSrequest=GetCapabilities Here is an example GetTile request: http:map1c.vis.earthdata.nasa.govwmts-antarcticwmts.cgi?TIME=2012-11- 20SERVICE=WMTSREQUEST=GetTileVERSION=1.0.0LAYER=MODIS_Ter ra_CorrectedReflectance_TrueColorSTYLE=TILEMATRIXSET=EPSG3031_250m TILEMATRIX=0TILEROW=0TILECOL=0FORMAT=image2Fjpeg If the TIME=parameter is omitted, it will return the current days tile when available Figure 2 — WorldView WMTS client implementation supporting Polar Stereographic projection It seems clear that nowadays it is not easy to find a consensus on a CRS based on the Polar Stereographic projection, nor a TileMatrixSet. Furthermore.there is no Mass